Silverback --
This is 1000 Yard Benchrest. Not often that you will see barrels shorter then 26". And most are 26" to 32" for reasons of accuracy and speed for our long heavy bullets that we use, no matter what the caliber.
Dan Lilja's barrel reputation speaks for itself in this sport. Since you are wanting one his barrels, I suggest calling or email him. He is good to give great answers! as are most manufactures in this sport.
Best of Luck with your build!!!
Happy Shooting
Donovan Moran